The invention relates to high vacuum evaporation and deposition systems, and more specifically to a device and method for cooling a crucible in an electron beam gun.
Electron beam guns have frequently been employed to evaporate material in a high vacuum environment for the purpose of ultimately depositing the material on a specific article or location. Such deposition systems typically include an electron emitting source, a crucible for holding the evaporant, and means for directing the electron beam onto the surface of the evaporant. Examples of such systems are described in U.S. Pat. Nos. 3,710,072, 3,235,647, and 3,420,977.
Prior art devices utilize a crucible cooling system consisting of a tubular channel of coolant 38 which flows around the crucible vicinity as shown in FIGS. 1 and 2. The inventors have determined that one of the primary problems with the prior art tubular cooling system is that it fails to uniformly cool the crucible. The result is that sections of the evaporant/crucible interface remain liquid causing crucible material to contaminate the evaporant.
Another problem with the prior art deposition systems is that in order to clean the crucible, the entire electron beam gun assembly must be removed from the vacuum and disassembled, requiring considerable time and effort